“One prominent credential seller in the underground peddles iTunes accounts for $8, and Fedex.com, Continental.com and United.com accounts for USD $6. Groupon.com accounts fetch $5, while $4 buys hacked credentials at registrar and hosting provider Godaddy.com, as well as wireless providers Att.com, Sprint.com, Verizonwireless.com, and Tmobile.com. Active accounts at Facebook and Twitter retail for just $2.50 apiece.”
Source:The Value of a Hacked Email Account — Krebs on Security